Deli-style double chocolate muffins

I've had a huge hankering for those massive double chocolate muffins you buy at the deli or grocery store--the ones as big as a grapefruit, super moist, oily even, with a crumb that pulls apart rather than, well, crumbling into a billion bits, and a chewy top. Definitely not springy or fluffy like a cupcake, and not crumbly like a healthy breakfast muffin. Decadent to eat plain, without frosting. Knowing that store-bought baked goods tend to have artificial ingredients, though, I want to bake my own. Trouble is, my current chocolate cake recipes don't have the right result, and the recipes I've seen online so far don't look like they'll do the trick. I have a hunch that using canola oil rather than eggs will play a role.

The closest I've had so far is the chocolate cake here, but it's still a little too tender-crumbled for my liking. (But if you haven't had it--make it! It is DELICIOUS with a salted caramel swiss meringue buttercream instead of the plain caramel filling.) http://www.marthastewart.com/857647/s...